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Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. IV: The Fourth Year (2011-2012)статья
- Авторы: Kato T., Hambsch F.J., Maehara H., et al, Voloshina I.B., et al.
- Журнал: eprint arXiv:1210.0678
- Год издания: 2012
- Первая страница: 1
- Последняя страница: 81
- Аннотация: Continuing the project described by Kato et al. (2009, arXiv:0905.1757), we collected times of superhump maxima for 86 SU UMa-type dwarf novae mainly observed during the 2011-2012 season. We confirmed the general trends recorded in our previous studies. There are some systems showing positive period derivatives despite the long orbital periods. We observed the 2011 outburst of the WZ Sge-type dwarf nova BW Scl, and recorded an O-C diagram similar to those of previously known WZ Sge-type dwarf novae. The WZ Sge-type dwarf nova OT J184228.1+483742 showed an unusual pattern of double outbursts composed of an outburst with early superhumps and one with ordinary superhumps. We propose an interpretation that a very small growth rate of the 3:1 resonance due to an extremely low mass-ratio led to a quenching of the superoutburst before ordinary superhumps appeared. We systematically studied ER UMa-type dwarf novae and found that V1159 Ori showed positive superhumps similar to ER UMa in the 1990s. The recently recognized ER UMa-type object BK Lyn dominantly showed negative superhumps, and its behavior was very similar to the present-day state of ER UMa. The pattern of period variations in AM CVn-type objects were very similar to short-period hydrogen-rich SU UMa-type dwarf novae, making them as helium analogue of hydrogen-rich SU UMa-type dwarf novae. SBS 1108+574, a peculiar hydrogen-rich dwarf nova below the period minimum, showed a very similar pattern of period variations to those of short-period SU UMa-type dwarf novae. The mass-ratio derived from the detected orbital period suggests that this system contains a brown-dwarf secondary if the white dwarf has a mass typical to dwarf novae. CC Scl, MASTER OT J072948.66+593824.4 and OT J173516.9+154708 showed only low-amplitude superhumps with complex profiles.
- Добавил в систему: Волошина Ирина Борисовна